Thank you for your help.
I should have given more information, sorry about that.
I'm using XP profesional, and pico version 5.12.1, and when looking at the version, I also see an error ADC 200 DRIVER V 4.02, ERROR 13 (H255 SO).
I'm using X10 probes, and taking the readings from the Oscope view. I tried to mesure with the meter view but couldn't get it to work? I've got the settings for probes at X10, and my 60hz trace reading is showing 160 VAC when measureing a 120 VAC line.
I took a 9V battery and switched my probes to X1, and got a perfect 9VDC reading. I switched my probe back to X10 and still got a perfect 9VDC reading. So it seams my probes are calibrated correctly. I also used the signal gen. output fromt he ADC 200 and got correct readings.
But when trying to measure the 120 VAC line, I read 160 VAC. I haven't checked the voltage at the probe with a hand held meter yet. I was going to try this using the pico meter view, but couldn't get it to work.